1 files changed, 40 insertions, 0 deletions
diff --git a/app/workers/container_registry/migration/observer_worker.rb b/app/workers/container_registry/migration/observer_worker.rb
new file mode 100644
index 00000000000..757c4fd11a5
--- /dev/null
+++ b/app/workers/container_registry/migration/observer_worker.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+module ContainerRegistry
+  module Migration
+    class ObserverWorker
+      include ApplicationWorker
+      # This worker does not perform work scoped to a context
+      include CronjobQueue # rubocop:disable Scalability/CronWorkerContext
+
+      COUNT_BATCH_SIZE = 50000
+
+      data_consistency :sticky
+      feature_category :container_registry
+      urgency :low
+      deduplicate :until_executed, including_scheduled: true
+      idempotent!
+
+      def perform
+        return unless ::ContainerRegistry::Migration.enabled?
+
+        use_replica_if_available do
+          ContainerRepository::MIGRATION_STATES.each do |state|
+            relation = ContainerRepository.with_migration_state(state)
+            count = ::Gitlab::Database::BatchCount.batch_count(
+              relation, batch_size: COUNT_BATCH_SIZE
+            )
+            name = "#{state}_count".to_sym
+            log_extra_metadata_on_done(name, count)
+          end
+        end
+      end
+
+      private
+
+      def use_replica_if_available(&block)
+        ::Gitlab::Database::LoadBalancing::Session.current.use_replicas_for_read_queries(&block)
+      end
+    end
+  end
+end